BRIGHT LIGHT: Although more energy-efficient than their incandescent counterparts, dimmable CFLs don’t yet have as wide a dimming range.

Q.I'd like to replace our dimmable floodlights with some of the dimmable compact fluorescent flood lights I've been seeing for sale lately. How do we know which ones to choose?

- Leila, VA

A. In the brave new world of CFLs, dimmability is an emerging technology whose kinks haven’t yet been completely worked out. Although decidedly more energy-efficient than their incandescent counterparts, dimmable CFLs don’t yet have as wide a dimming range. Rather than running the gamut from totally switched-off to full steam ahead, CFLs can move only between 20 and 90 percent of full brightness. That’s because if you reduce the power streaming into a CFL too much, its filament can cool off to the point that the bulb stops working and simply turns off, according to the Environmental Defense Fund.

Be warned that not all CFL’s advertised as dimmable will necessarily jive with your setup. You’ll want to test out any bulb you buy, so be sure to find out the seller’s return policy before buying bulbs, and keep your receipts incase you need to go back and try another model. And before you hit the store, check out this helpful Environmental Defense Fund site, which details specific CFL-bulb makes and models, including floodlights, from brands such as GE, Philips and MicroBrite. The page also includes helpful product reviews from users.

So where to buy bulbs? CFL technology might be space-age futuristic, but this is one of those situations in which the human touch can really help. Look for specialty lighting companies in your area — not just hardware stores, but bulb specialists, who can talk you through the products and the process. “Your ordinary place that just sells ordinary bulbs wouldn’t have anything as specific as a dimmable CFL flood for a recessed area,” says Doralee White of White Electric Company in Berkeley, California. Her company has a toll-free number and ships nationwide at no extra charge. “There’s a tremendous variety out there,” she says, “and it’s hard to choose.” Might as well let an expert help.

Story by Anneli Rufus and Kristan Lawson. This story originally appeared in Plenty in May 2008.